Previous work has focused on the input-facilitating orienting response (OR) to the virtual exclusion of the complementary, input-limiting "protective" system consisting of defensive (DR) and startle (SR) responses. We will expand this work by beginning detailed study of DR and SR, together with OR function in schizophrenia. We will also start systematic comparisons of depressives and schizophrenia in each of these functions. Exploring the nature of OR, DR, and SR in schizophrenics, depressives, and normals, we will check possibilities raised by existing data: 1) that schizophrenics electrodermally "OR-responsive" to innocuous stimuli may actually be responding with DR/SR instead, or otherwise displaying bias toward "protective" rather than OR response; 2) that electrodermally OR-nonresponsive schizophrenics may be displaying DRs or similar bias; 3) that, by making an otherwise DR-eliciting stimulus the potential carrier of significant information, excessive DR activity among schizophrenics may be reduced and replaced with normal-like ORs; 4) that depressives may show frequent OR nonresponsiveness to innocuous stimuli, similar to that of schizophrenics, which also generalizes across OR-components but, 5) does not "normalize" when significant signals are used, thus still differentiating depressives from schizophrenics in OR function; and, 6) that depressives, unlike schizophrenics again, show below-normal DR and SR activity as well. Our previous work exploring symptom-patterns associated with OR dysfunction will be extended to include DR and SR as well, and information will be obtained on the effects of anti-psychotics and anti-depressants here. Measurements involve electrodermal, finger pulse volume, heart, rate, forearm girth, and eyeblink activity. Since drowsiness can bias responding, this will be examined from background EEG and skin conductance levels throughout each study. Subject ratings of stimulus unpleasantness during each study will be compared, and their effect on response type determined.